I've only seen it once, and I wasn't particularly impressed with it. I think it was an early episode and I was informed that it wasn't a very good one. I understand it was kind of revolutionary at the time, but it felt very dated in 2005 or whenever I saw it.

I used them in the distant past and mostly met weirdos. Some funny stories, some really creepy ones. Back in the day I used OKCupid, Nerve (not sure if this still exists?), Yahoo Personals (which I think was bought by Match.com) and probably some others I'm forgetting.